Methods for the controlled shrinkage of textile fabrics



July 11, 1967 J. H. SlEBER 3,330,015

METHODS FOR THE CONTROLLLED SHRINKAGE OF TEXTILE FABRICS Filed May 8,1963 2 Sheets-Sheet 1 Fig: 1.

DISTILLING UNIT FILTER F RESERVORR 24 PROGRAMMER INVENTOR.

JOHANNES H. SIEBER Jfissiem, jam (5 Jdaalzm July 11, 1967 J. H. SIEBER3,330,015

METHODS FOR THE CONTROLLLED SHRINKAGE OF TEXTILE FABRICS Filed May 8,1965 2 Sheets-Sheet 2 V OP V6 INVENTOR. JOHANNES H. SIEBER BY Jlulem; 3L

United States Patent 3,330,015 METHODS FOR THE CONTROLLED SHRINKAGE 0FTEXTILE FABRICS Johannes Helmut Sieber, Neusass, near Augsburg, Germany,assignor to Firma Biihler & Weber KG., Augsburg, Germany, a corporationof Germany Filed May 8, 1963, Ser. No. 278,955 Claims priority,application Germany, Dec. 23, 1960, B 60,633 3 Claims. (CI. 2619) Mypresent invention relates to a method of controlledly treating a fabricwith water and is a continuation-inpart of my copending application Ser.No. 160,640 filed December 19, 1961, and now abandoned.

In this copending application I disclose a process for the milling andafter-treatment of fabrics with water wherein the water is transferredonto the fabric from a liquid vehicle, containing a dry-cleaningsolvent, in which the water formed a dispersion. This technique has beenfound to have general applicability in the shrinkage of nonwool fabricsas well as those containing wool, for the impregnation of fabrics withvarious treating agents and other fabric-finishing steps in addition tothe milling or fulling mentioned above.

Generally speaking, treatment of fabrics with water has been carried outheretofore by immersing and agitating the fabric in a water bath. Thismethod, by virtue of the fact that an excess of water is always presentin contact with the fabric, is complicated by a number of variables, allof which must be controlled for effective milling. In the direct watertreatment of fabric, for example, temperature is of prime importancesince wool, cotton, viscose rayon and like fabrics swell more rapidlywith increasing temperatures. The shrinkage effect is also moresignificant in hot water than in cold water. When wool fabrics areinvolved, felting occurs very rapidly in the presence of pure water sothat extremely close control over the treatment time is essential.Additionally, in a pure aqueous medium, control over pH must be observedif reproducibility is to be insured. As a consequence of theaforementioned complications arising from the aqueous milling offabrics, the industry has long sought to control the several variablesin a convenient manner and to eliminate as variables as many factors aspossible. Efforts to eliminate controllable and uncontrollable variablesin the treatment of fabrics in general have led to only limited successheretofore. It may, for example, be noticed that the impregnation offabrics with water-soluble material in the presence of a purely aqueousmedium has shown that considerable care must be taken with respect tothe same variables which governed milling action.

It is an object of the present invention to provide an improved methodof milling wool-containing fabrics.

Another object of this invention is to extend the principle advanced inmy above-identified copending application to the controlled treating offabrics in general.

Still another object of this invention is to provide an improved methodof treating fabrics with water-soluble treatment agents.

A further object of my invention is to provide a process forcontrolledly shrinking fabrics.

Yet another object of this invention is to provide an improved apparatusfor treating fabrics and milling woolcontaining textiles.

These objects and others, which :will become more readily apparenthereinafter, are attained, in accordance with the present invention, bya method of treating fabrics wherein water is dispersed in a liquidvehicle in which it is only slightly soluble but in the presence of aquantity of a surface-active agent sufiicient to stabilize the waterdispersion but less than that required to solubilize the water. Thefabric is then immersed in the liquid vehicle and absorbs watertherefrom while being agitated therein, e.g. by tumbling.

I have discovered that, under these circumstances, water completelysaturates the liquid vehicle or solvent so that the latter can always beconsidered to possess a humidity of 100% at the operating temperature.Since the amount of water which will saturate the solvent is welldefined, no difiiculties arise from excess moisture or insuflicientmoisture. The liquid vehicle is preferably composed entirely of adry-cleaning solvent of conventional type since such solvents arereadily removed from the fabric and have a water-saturation pointwherein the water content is not insignificant but yet below the levelat which undesirable efi'ects will result. As the fabric absorbsmoisture from the solvent, additional water in a dispersed state, butnot yet in solution, dissolves to maintain saturation of the solvent. Aspreviously pointed out, the surface-active agent is present insufiicient quantity to stabilize the water dispersion but not in aquantity capable of solubilizing it within micelles of the surfactant.

I am aware that earlier efforts in the dry-cleaning industry haveinvolved the used of surface-active agents to stabilize and increase thequantity of water dispersed within a dry-cleaning solvent. It must benoted, however, that these efliorts were based upon an entirelydifferent principle of operation from that involved in the presentinvention. It is an essential aspect of such dry-cleaning processes thatwater be provided in the solvent to remove water-soluble soils, thewater being provided in a substantial proportion of the dry-cleaningsolvent. To insure that the soils dissolved by the water were removedand prevented from again depositing upon the fabrics, sufficientquantities of a surface-active agent were provided to solubilize thewater in micelles. In such methods the quantity of surface-active agentwas invariably greater than the quantity of water to insure totalsolubilization and, in fact, was often ten to twenty times greater thanthe quantity of water it was desired to solubilize. Incontradistinction, the present invention derives from the discovery thatwater can be dispersed in a dry-cleaning solvent in the presence of aquantity of surface-active agent less than that of water and sufiicientonly to stabilize the dispersion but incapable of solubilizing the waterso that dispersed water is free to go into solution in the solventwithout dissolving in the surface-active agent. In dry-cleaning systemsoperating with the aid of water, moisture solubilized in surfactantmicelles is prevented from freely dissolving in the organic solvent asrequired.

According to a further feature of the present invention, the liquidvehicle, consisting predominantly of the drycleaning solvent, iscirculated through the fabric and the water dispersed thereinreplenished during this circulation. I have discovered that excellentresults are obtained when the dry-cleaning machine or immersionreceptacle in which the treatment of the fabric is carried out isprovided with a solvent-circulating system including pump means capableof effecting a fine dispersion of the water in the solvent and supplymeans for the water and/ or the surface-active agent is disposedrearwardly of the pump in the direction of circulation of the liquid.Advantageously,

the system can be provided with means for extracting the liquid vehiclefrom the fabric at the conclusion of the treatment process, controlmeans being provided to direct a portion of the solvent removed from thetreatment vessel to a distilling means for purification. Preferably, thefree liquid within the receptacle is first drained into a storage tankor reservoir with only the tailings, removed by extraction, being fed tothe distilling device.

As previously indicated, the quantity of surface activation may be equalto a small fraction of that of the dispersed water (between 0.1 and 10%by weight of the fabric to be treated), the water being present in ana-mount ranging between substantially and 50% by weight of the fabric.Best results are obtained when the liquor ratio, i.e. the ratio offabric in kilograms to total liquid vehicle in liters, ranges between1:2 to 1:50 and preferably .is about 1:10. The relative quantities ofwater dispersed in the dry-cleaning solvent and surface-active agent aremore dramatically demonstrated by noting that the preferred range ofsurfactant quantities lies between 0.5 and 3% by weight of the fabricwhile the water quantity is between 5 and 20% by weight of the fabric.

7 Almost any dry cleaning solvent is suitable for carrying out theprocess of the present invention, it being noted that solvents in whichwater is only slightly soluble are the most satisfactory. The mostpractical solvents for use in treating fabrics in the manner describedabove are the chlorinated hydrocarbons and solvent mixtures containingaliphatic, aromatic and alicyclic hydrocarbons of the Stoddard type.Solvents having particular suitability are those described in ASTMStandards D484-52 and hereafter designated as Stoddard solvents. Of thechlorinated hydrocarbons, perchlorethylene and trichlorethylene are.

most suitable since they are readily removed from the fabric at theconclusion of treatment by conventional means.

According to another aspect of the present invention, the waterdissolved in the dry-cleaning solvent'serves as a carrier forwater-soluble adjuvants for treating the fabric. In this case theadjuvant, which can be a syntheticresin stiffening agent, a softeningmedium or any other water-soluble substance with which it is desired totreat the fabric, is added to the solvent subsequently to the dispersionof the water and surfactant therein or concurrently with suchdispersion. The adjuvant is found to dissolve in the dispersed Water andto be carried with it onto the fabric as the dispersed water itselfdissolves in the solvent upon withdrawal of water therefrom by thehydrophilic fabric.

Still another feature of the present invention resides in the treatmentof both Wool and other fabrics by this technique for controlledlyshrinking them to the desired dimensions. Whereas the present techniqueis particularly suitable for milling and felting wool-containingfabrics, it should be noted that treatment of fabrics with water is moregenerally applicable. Thus, cotton fabrics may be treated, according tothe invention, with water in a solvent vehicle as described above toshrink the fabric in a controlled manner with time and temperature beingthe sole, variables determining the quantity of water absorbed by thecotton fabric. In this connection it may be pointed out that directimmersion of cotton fabrics in water often results in an uncontrolledshrinkage since many other factors enter into the determination of thequantity of water absorbed by the fabric and affecting shrinkagethereof. Again adjuvants may be carried by the water to the cottonfabric in order to treat the latter.

The surface-active agents employed in the present method includeanionic, cationic and noniouic types as well as conventional soaps. Itis desirable, for the most part, to operate at about room temperaturewhen milling and fabric shrinkage are. to be carried out, but at highertemperatures (say 30-40 C.) when felting is required.

a It may be noted that the organic solvents to be used have awater-saturation level on the order of 0.04% by weight at 25 C., apreferred temperature for milling Wool-containing fabrics. I

The above and otherobjects, features and advantages of thepresent-invention will become more readily apparent from the followingdescription and examples, reference being made to the appended drawingin which:

FIG. 1 is an axial cross-sectional view through a drycleaning machine ofthe rotating-basket type, schematically showing a system embodying thepresent invention;

FIG. 2 is a graphof the sequence of operation of the FIG. 3 is a diagramillustrating another apparatus for carrying out the present method.

In FIG. 1, 'I show a dry-cleaning machine '10, of a generallyconventional type, wherein a receptacle 11 encloses a rotatingfabric-receiving basket 12 into which the fabric 13 can be introducedvia an opening 14 in the receptacle which can be closed by a door 15.The perforated basket 12 is provided with vanes 16 for agitating thefabric in the liquid 17 contained by the receptacle. The basket 12 isprovided with a driven pulley 18 connected via a belt 19 with the drivewheel 20 of a motor M whose two-speed transmission 22 is normally in itslow-speed state. An electromagnetically operable clutch C is provided onthe transmission for shifting it to its high speed. The motor M alsocarries a pump for'draining solvent from the receptacle 11.

another pipe 26 whereby regenerated solvent can be drained into thereservoir'24 by gravity. A conduit 27 leads from the outlet of the pumpand supplies a first duct means 28 via an electrically operable valve Vto convey the liquid vehicle to the distilling unit D. A second ductmeans 29, having an electrically operable valve V is also provided toconvey the liquid directly to the reservoir 24. A conduit means 30 withits valve V forms with line 27 and pipe 25 a closed system forcirculating the solvent, as will be described hereinafter.

The intake end of pump 23 is fed by a drain pipe 31 from the receptacle11 and serves as the termination for a supply line 32 whose gravity-feddispenser 33 adds water and surfactant to the solvent. The amount ofwater added can be determined by a manually adjustable valve 34,although sensing means 35, responsive to the water content of thesolvent, may be provided in line 27 for automatic control of this valve.A two-position cntofi valve V is provided in supply line 32 forinitiating and halting flow of water into the solvent. a A filter F,whose inlet 36 is connected to line 27 'via an electromagneticallyoperable valve V can also be provided to remove solid and certain liquidimpurities from the solvent stream as desired. The outlet pipe 37 offilter F contains a check valve 38 toprevent backflow of the liquid. Anair-inlet duct 39, supplied by a blower not shown, is fitted with anelectrically controlled valve V for supplying a blast of drying air tothe receptacle 11. An outlet duct 40 is designed to carry air saturatedwith the solvent to the distilling unit D for recovery of the solvent. Atimer and programming means 41, which can be of the card-control type,is provided for sequentially operating the valves. Such programmers arewell known per se and need not be described in detail.

The operation of the apparatus of FIG. 1 will now be described withreference to a five-minute milling opera tion. The programming sequencemay, of course, be altered as desired to suit anyparticularrequirements. The

fabric, e.g. wool-containing garments to be milled, is introduced intothe basket 12 via opening 14 and the door, 15 then closed. Theprogrammer is then turned on to and not shown herein. Afterapproximately three-quarters of a minute (FIG. 2), a period sufiicientto permit intro-. duction of the desired quantity of solvent, valve Visclosed and valve V opened. Valve V has meanwhile been energized sothat the pump 23 circulates the drycleanrng solvent from and back to thereceptacle 11. This pump is preferably of the centrifugal type to ensurethorough agitation of the solvent. Concurrently with or shortly afterthe actuation of valve V valve V is opened to admit water and surfactantfrom the supply means 33 into the solvent stream rearwardly of the pump23 in the direction of circulation of the liquid. The pump thusconstitutes a dispersing means which forms a fine dispersion of water inthe solvent. The water, carried by the solvent, is thus brought intocontact with the fabric 13 as the drum rotates at low speed for theduration of the milling operation shown to be approximately 4 minutes.

At the five-minute point, valves V and V; are closed while valve Vremains open and either valve V or V is opened. The pump then displacesthe free solvent of receptacle 11 into reservoir 24 directly or into thelatter via the filter F. Solvent trapped in the fabric 13 is not,however, drained from the receptacle 11 at this time. Afterapproximately one minute of draining, valve V or V is closed and valve V'opened concurrently with energization of clutch C and the distillingunit D. This energization of clutch C shifts the transmission 22 intoits high speed whereupon the basket 12 is rotated rapidly to forceliquid out of the fabric 13 by centrifugal force. This liquidconstitutes the tailings and is conveyed by pump 23 to the distillingunit D via line 28 whose valve V, has been opened as previously noted.When the extraction stage has been completed, clutch C is de-energizedand valve V closed and the basket 12 rotated again at low speed totumble the fabric 13. The valve V is then operated to admit a stream ofdrying air, heated is desired, to the receptacle 11. As the fabricdries, the solvent-containing gas is carried to the distilling unit Dwherein the solvent is recovered. At the conclusion of the operatingcycle, motor M is cut off and the fabric removed.

In FIG. 3 I show an arrangement wherein a fabric 42 can be continuouslytreated. The fabric can be drawn from a supply roll 43 or from earlierprocessing apparatus and passes into a receptacle 44 containing thesolvent 45 in which water and a surface-active agent are dispersed. Anoutlet tube 46 conveys a solvent to a pump 47 which circulates it backto the receptacle 44. A dispenser 48 is provided to feed water andsurfactant to the conduit means 36 etc. rearwardly of pump 47 butforwardly of the receptacle 44. A wheel 49, with radially extending arms50, serves to agitate and maintain the fabric 42 below the level of theliquid 45 for a period sufiicient to carry out the desired treatment.From the receptacle 44 the fabric can pass into a drying zone 51 whereinblowers 52, diagrammatically shown, remove the solvent which can berecovered and returned to the tank. A distilling unit or reservoir maybe provided as shown in FIG. 1.

EXAMPLE I In a dry-cleaning machine of the aforedescribed type (FIG. 1),I dispose 4 kg. of a wool-containing knitwear, consisting substantiallyof 70% wool and 30% viscose rayon. The knitwear is in a damp state andcontains 11.5%, by weight, of water. The drycleaning machine is chargedwith a perchlorethylene cleaning solvent at a liquor ratio of 1:10 (forone kilogram of goods ten liters of solvent). A quantity of asurface-active agent equal to 1% of the weight of the fabric isdistributed in the solvent. It should be noted that the water/surfactantweight ratio is approximately 11521. An anionic emulsifier (sodiumdodecylbenzinesulfonate) serves as the stabilizer for the dispersion.The milling time is approximately 15 minutes. The dried knitwear isfound to have been milled to the desired extent without undue felting.

EXAMPLE II A woven fabric containing approximately 70% wool is treatedin the dry-cleaning machine with Stoddard solvent (ASTM 13484-52) at aliquor ratio of 1:5 (for one kilogram of fabric five liters of solvent).Approximately 14 kg. of fabric are treated. A paste soap (560 cc.)containing 75 g. of water is then added. In this case it is desirablethat a total water content of 17%, based upon the weight of the fabric,be employed. Approximately 2.3 kg. of water must then be added to thedry-cleaning solvent together with or subsequent to the addition of thesoap at the supply means whereupon the water is dispersed thoroughly inthe solvent by the pump. The fabric is milled for 15 minutes whereuponthe solvent is drained to the reservoir, and is then extracted for 3minutes, the liquid tailings being conducted to the distilling unit.Again the dried fabric shows the desired milling effect.

EXAMPLE HI 18 kg. of woolen blankets, consisting of 30% by weight cottonand 70% by Weight wool, just olf the loom and still containing size andnatural oils, are treated for 5 minutes in 360 liters oftrichlorethylene dry-cleaning solvent (liquor ratio 1:20). The blanketsare then extracted, with the solvent distilled and returned to thereceptacle by way of the pump which disperses 360 g. of a nonionicemulsifier (a nonylphenylethyleneoxide condensate such as the onemarketed under the trademark Tergitol NPX) together with 2.2 liters ofwater (approximately 12% calculated on the weight of the blankets) inthe recirculating solvent stream. After milling of the fabric in thissolution for 5 minutes, the spent liquor is returned to the reservoirwith the tailings being passed through the distilling unit. After dryingfor 20 minutes at 80 C., the blankets are found to be not only clean butalso free of size and provided with the desired milling effect so thatonly a final napping treatment is necessary to finish the fabric.

EXAMPLE IV A wool cardigan is milled in a perchlorethylene solvent(liquor ratio 1:10) in the presence of 12% water based upon the weightof the fabric. About 1% by weight of the fabric of a quaternary ammoniumcompound (as a cationic surface-active agent) stabilizes thewater-insolvent emulsion. The quaternary ammonium compound is acommercially available substance such as that marketed by Armour & Co.under the trade name Arquad HT and containing long-chain alkyl groups. Amilling time of approximately 12 minutes in used. If it is desired toapply a filler or softener to the fabric, this adjuvant can be dissolvedin the vehicle for transfer to the fabric by the Water dispersedtherein. For example, approximately 0.8% by weight of the fabric ofdextrin can be dissolved in the system just described for the treatmentof a woven fabric consisting of 30% viscose rayon and 70% wool.Substantially all of the dextrin dissolved in the vehicle is depositedin the fabric and adsorbed thereby.

EXAMPLE V A l00%-wool material is felted in the dry-cleaning machine orreceptacle of FIGS. 1 or 3 with a perchlorethylene liquor ratio of 8:1.The solvent contains 40% Water, based upon the weight of the fabric, andthe aforedescribed nonionic emulsifier is used. The treatmenttemperature is 40 C. A stiffening adjuvant (10% by weight of the fabricof polyvinyl alcohol) is added to the vehicle for transfer to the feltby the dispersed Water. After at least partial drying the felt can beblocked and set.

EXAMPLE VI A cotton-knit fabric is agitated for 5 minutes inperchlorethylene (liquor ratio 1:10) in the presence of a softening-typesurface-active agent. Approximately 1% of the weight of the fabric ofthe sulfated diisobutylamide of oleic acid marketed under the trademarkHumectol is used as the surfactant and serves to stabilize an emulsionof 35% water, by weight of the fabric, in the solvent. The fabricshrinks by about 6% to the desired dimensions.

I claim:

1. A method of treating, with controlled shrinkage, a water-absorbentfabric, comprising the steps of dispersing Water in an organic vehiclecontaining a dry-cleaning solvent, in which said water is only slightlysoluble, in the presence of a quantity of a surface-active agent sufficient to-sta'bilize the Water dispersion but lessthan that required tosolubilize said water, whereby dispersed insolubilized water enters intosolution in said solvent to maintain said solvent saturated with water,the quantity of water ranging between substantially and 50% by weight ofthe fabric, the liquor ratio ranging between substantially 1:2 and 1:50,and the quantity of surfaceactive agent ranging between substantially0.1 and of the weight of the fabric;

immersing and agitating said fabric in said vehicle with the waterdispersed therein under controlled conditions of time and temperaturecompatible with the fabric treated;

adding to said vehicle further quantities of water and said agentsufiicient to replace water absorbed from said vehicle by said fabric;

separating the fabric from said vehicle; and thereafter drying saidfabric.

2. A method of treating, with controlled shrinkage, a water-absorbentfabric, comprising the steps of dispersing water in an organic vehiclecontaining a dry-cleaning solvent, in which said water is only slightlysoluble, in the presence of a quantity of a surface-active agentsufficient to stabilize the waterdispersion but less than that requiredto solubilize said water, whereby dispersed insolubilized water entersinto solution in said solvent to maintain said solvent saturated withwater, the quantity of water ranging between substantially 5 and 50% byWeight of the fabric, the liquor ratio ranging between substantially 1:2and 1:50, and the quantity of surfaceactive agent ranging betweensubstantially 0.1 and 10% of the weight of the fabric;

immersing and agitating said fabric in said vehicle with the waterdispersed therein under controlled conditions of time and temperaturecompatible with the fabric treated;

, dissolving in said vehicle an adjuvant soluble in the water dispersedin said vehicle for transfer by the dispersed water to said fabric;

separating the fabric from said vehicle; and thereafter drying saidfabric.

, 3. A method of treating, with controlled shrinkage, a

water-absorbent fabric, comprising the steps of dispersing water in anorganic vehicle containing a dry-cleaning solvent, in which said wateris only slightly soluble, in

the presence of a quantity of a surface-active agent equal to a smallfraction of that of the dispersed water and sufiicient to stabilizethewater dispersion but less than that required to solubilize said water,whereby dispersed insolubilized water enters into solution in saidsolvent to maintain said solvent saturated'with water, the quantity ofwater ranging between substantially 5 and by weight of the fabric, theliquor ratio ranging between substantially 1:2 and 1:50, and thequantity of surfaceactive agent ranging between substantially 0.1 and10% of the weight of the fabric;

immersing and agitating said fabric in said vehicle with the waterdispersed therein under controlled conditions of time and temperaturecompatible with the fabric treated; V dissolving in said vehicle anadjuvant soluble in the water dispersed in said vehicle for transfer bythe dispersed water to said fabric; separating the fabric from saidvehicle; and thereafter drying said fabric.

References Cited 5 ROBERT R. MACKEY, Primary Examiner.

DONALD W. PARKER, MERVIN STEIN,

Examiners.

1. A METHOD OF TREATING, WITH CONTROLLED SHRINKAGE, A WATER-ABSORBENTFABRIC, COMPRISING THE STEPS OF DISPERSING WATER IN AN ORGANIC VEHICLECONTAINING A DRY-CLEANING SOLVENT, IN WHICH SAID WATER IS ONLY SLIGHTLYSOLUBLE, IN THE PRESENCE OF A QUANTITY OF A SURFACE-ACTIVE AGENTSUFFICIENT TO STABILIZE THE WATER DISPERSION BUT LESS THAN THAT REQUIREDTO SOLUBILIZE SAID WATER, WHEREBY DISPERSED INSOLUBILIZED WATER ENTERSINTO SOLUTION IN SAID SOLVENT TO MAINTAIN SAID SOLVENT SATURATED WITHWATER, THE QUANTITY OF WATER RANGING BETWEEN SUBSTANTIALLY 5 AND 50% BYWEIGHT OF THE FABRIC, THE LIQUOR RATIO RANGING BETWEEN SUBSTANTIALLY 1:2AND 1:50, AND THE QUANTITY OF SURFACEACTIVE AGENT RANGING BETWEENSUBSTANTIALLY 0.1 AND 10% OF THE WEIGHT OF THE FABRIC; IMMERSING ANDAGITATING SAID FABRIC IN SAID VEHICLE WITH THE WATER DISPERSED THEREINUNDER CONTROLLED CONDITIONS OF TIME AND TEMPERATURE COMPATIBLE WITH THEFABRIC TREATED; ADDING TO SAID VEHICLE FURTHER QUANTITIES OF WATER ANDSAID AGENT SUFFICIENT TO REPLACE WATER ABSORBED FROM SAID VEHICLE BYSAID FABRIC; SEPARATING THE FABRIC FROM SAID VEHICLE; AND THEREAFTERDRYING SAID FABRIC.